Review of ‘Quanta: Thermodynamics of Life’

I recently stumbled upon an article on Quanta titled How Life (and Death) Spring from Disorder and fell in love with it. The evolution of life is but an inevitable consequence of ever-increasing entropy and life can be seen as a computational process to optimize energy extraction from surroundings. Similarly, evolution can be defined as the selection of agents that maximize thermodynamic efficiency, sometimes at the cost of precision.  All biological processes can be explained using physics, even the seemingly inexplicable parts like intention and subjective experience.

My interest in this essay is owed to 3 main concepts: ‘agents’ in the decision theoretic sense, the Bayesian nature of the second law of thermodynamics, and how a maximum entropy heat death of the universe makes a mockery of someone (such as me) seeking immortality.

John Baez once defined life as self-replicating information about how to self-replicate and this essay does justice, in part, to that definition. Considering these replicators to be agents, defined as systems extracting thermodynamic work from their environment, it also suggested that natural selection has selected for agents that minimize the thermodynamic cost of computation, an idea I first encountered while learning the glycolysis pathway and it never ceases to amaze me.

Can agents be defined as systems that extract thermodynamic work from their environments (which in turn gives them the ability to extract even more thermodynamic work)? An agent, then, would be a prediction machine that predicts the positions of particles around it in phase space and uses that information to extract work and maintain a state of order against the tides of increasing entropy.

I was extremely intrigued to see this definition of evolution in terms of both thermodynamics and decision theory and I believe this line of reasoning could help us unravel the mystery of how life first emerged on Earth, rebuking the vacuous ‘elan vital’ model yet again.

Above all,

I had often hoped to disprove the law of increasing entropy because the heat death of the universe and immortality are incompatible.  I sought hope in Maxwell’s Demon until Engines of Cognition ripped it apart piece by piece. Information must be stored physically, computation on information also increases entropy and the second law of thermodynamics is invincible. Sir Arthur Eddington spoke of wanderers and cranks like my former self: 

If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations — then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.



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